dm: video: Flush the cache after a puts()

This helps keep the display consistent. puts() is used when printing the
prompt, so is a useful way to make sure the current display contents is
visible.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Tom Warren <twarren@nvidia.com>

drivers/video/vidconsole-uclass.c

@@ -170,6 +170,7 @@ static void vidconsole_puts(struct stdio_dev *sdev, const char *s)
 
 	while (*s)
 		vidconsole_put_char(dev, *s++);
+	video_sync(dev->parent);
 }
 
 /* Set up the number of rows and colours (rotated drivers override this) */